Flue cleaner



June 20, 1939; w STEVENS 2,163,384

FLUE CLEANER I Filed May 15, 1936 INVENTOR fownRo l V; STE l/E/vs.

ATTORNEY Patented June 20, 1939 UNITED STATES PATENT OFFICE FLUE CLEANERApplication May 15, 1936, Serial No. 80,023

1 Claim.

This invention relates to a flue cleaning tool operated by areciprocating motor. The present invention is designed to meet thedemand for a practical tool to remove carbon deposits in oil still tubesof two inches or less in diameter, but is applicable also to tubes oflarger diameter. An object of the invention is to increase theefficiency of machines of this type.

Another object is to operate the cutting tool by reciprocating impulsesimparted to it by the cylinder of a fluid pressure motor. In accordancewith this object, the cutting tool is arranged to be carried by thecylinder and to vibrate therewith in response to the recoil produced bythe piston at the end of each stroke.

A feature of the invention resides in a novel form of cutter comprisingjaws yieldingly held in contact with the inside of the tube and havingon its periphery cutting teeth arranged in circumferential and spiralrows.

Another object is the provision of a flue cleaning tool that is simplein construction, inexpensive in manufacture and efiecstive in operation.

Other objects and features of the invention 25 will appear more clearlyfrom the following description taken in connection with the drawing andappended claim.

In the accompanying drawing:

Fig. 1 is a longitudinal sectional view of the flue cleaning tool inoperative relation to a tube.

Fig. 2 is a longitudinal view partly in elevation and partly in sectionof the cutting element of the tool, and 35 Fig. 3 is an elevational endview of the cutting tool shown in Fig. 2.

Referring to the drawing, the illustrative embodiment of the inventioncomprises a cylinder ID in which a piston II reciprocates. The cylinderhas a backhad I2 threadably connected thereto and locked by a springpressed lock pin I3. The interior of the cylinder is defined by a boreIlla and a counterbore Illb adapted to fit the piston extension Ila andpiston head Ill) 45 respectively. The counterbore It?) provides a pistonchamber which is supplied with live air through an inlet port I I nearits front end and which is in communication with an exhaust port I5toward the rear end. A hose I6, screwed to 50 the backhead I2, suppliespressure fluid through passages l'I, I8 and I9 in the cylinder to theinlet port I4. A longitudinal passage in the cylinder connects two ports20a and 20b to provide a by-pass for live pressure fluid around thepiston 5 head Ilb when the latter lies between said ports,

and thereby admits pressure fluid behind the piston. The piston II has acapacity chamber 22 which is closed at its front end but communicateswith the piston chamber IIlb at the rear end of the piston. is Theadmission of compressed air through the hose I6 results in vibratingcylinder IIl, the cycle of operation being as follows: Live airdelivered by the hose is conducted through passages I! and I8 in thebackhead I2, cylinder passage I9 and m inlet port I4 to the pistonchamber IIlb in front of the piston head II b, thereby causing thepiston to move rearwardly. When the piston head has moved rearwardly touncover the port 201), live air passes around the piston head IIb'through 15 port 20?), passage 20 and port 20a to the rear end of thepiston chamber and fills the capacity chamber 22 in the piston as wellas the space in back of the piston. Due to the fact that the rearsurface of the piston II is of greater area than 20 the opposing surfaceat the front end of the head lIb exposedto live pressure fluid, thepiston will reverse and move forward with great speed until stopped byreason of the fact that the piston head on its forward movement cuts offthe live 25 air through inlet port I4 and opens exhaust port I5. Thedrop in pressure behind the piston and the building up of pressure onthe forward ends of both piston head I lb and piston extension I la stopthe piston in its forward movement and return it to the rearwardposition to repeat the cycle. A vent port 24 in the cylinder bore Illaacts as a breather hole to permit air within the bore I00, forward ofthe piston extension to surge in and out according to the movement ofthe piston. The port 24 is spaced from the front extremity of thecylinder bore Illa and is designed to be covered by the piston so thatair will be trapped to form a cushion 25 to stop the piston in itsforward movement. A similar cushion 26 is provided at the rear end ofthe piston chamber IIlb in back of the port 2001..

When the piston strikes the front cushion 25 it delivers a blow theretojarring the cylinder I0 forwardly. The forward movement of the cylinderis further augmented by the expansion of live air in front of the pistonhead Ilb as the piston starts to move rearwardly. Similarly, thecylinder is jarred rearwardly by the momentum of the piston and theadmission of live air in back of the piston as the latter reaches theend of its rearward stroke. I The vibrations of the cylinder IIl, causedby the action of the piston and pressure fluid, are utilized to operatea cutting tool 28 connected to the front extremity of the cylinder andvibrating in unison therewith. The cutting tool is mounted on thecylinder extension 29 which is provided with two annular grooves 30 and3|. The cutting tool has the general shape of a cylinder, on the rearend of which is formed a flange 32 adapted to seat in the groove 30. Inthe form shown (see Fig. 3), the cutting tool is made up of eightdetachable segments 33, the longitudinal edges of which extend spirally.

The segments are urged outwardly by an expanding spring 35 made ofrubber or other suitable material. In the form shown, the rubber is ofannular shape to fit the recess 3| in the cylinder extension 29 andengage the interior surface of the segments 33. Wire rings 36 mounted incooperating grooves in the segments 33 retain the cutter segments inassembled position when not in use.

The peripheral surface of the cutting tool 28 is partly cylindrical andpartly tapered. Cutting teeth 37 are provided on the outside surface ofsegments 33, said teeth being defined by circumferential grooves 38 andlongitudinal grooves 39, the longitudinal grooves being parallel to thespiral edges 34.

The cutting tool 28, which is preferably made of steel, is first formedin one piece and milled to provide the teeth 31 and slots 43. The slots40 are of such depth that small connectingportions 4| are provided onthe flange 32. The cutter is hardened as a unit and then broken up intosegments 33. After the cutter is assembled on the support 29, theportions 4| act as spacers to keep the sections equally divided inassembled position The cutting tool 28 and cylinder are inserted as aunit into a tube 42 which is lined with a carbon deposit 43. The taperedsurface of the cutting tool permits the latter to contract slightly tothe size of the tube. The entire device may be reciprocated bymanipulating the hose [6.

When air is admitted through the hose, the cylinder and cutting toolvibrate in unison in response to the reciprocations of the piston l l,as previously described. The vibration of the cutting tool results in anabrading action of the cutting teeth 31 to remove the carbon deposits 43from the tube. Due to the spiral arrangement of the grooves 39 and slots40, the entire area of the inside surface of the tube 42 is covered bythe cutting teeth.

The cutter grooves 38 and 39 and slots 40 provide a means of escape forthe particles removed by the abrading action. The carbon particles areremoved from the cutter by a stream of exhaust air from the cylinderIll. The air is conducted to the cutter by means of a longitudinalpassageway 45 in the cylinder receiving the exhaust air from ports and24 and discharging the air against the cutting tool 28. An annular space43 between the cutting tool and cylinder l0 permits the exhaust air tocirculate so that it will pass over the entire peripheral surface of thecutting tool.

While the invention has been particularly described with reference to asingle illustrative embodiment, it will be apparent that many changesand adaptations may be made within the spirit of the invention andwithin the scope of the appended claim.

What is claimed is:

A tube cleaner comprising a cutting tool having a cylindricalcuttingsurface adapted to engage the interior of a tube, said cuttingsurface having longitudinal grooves, a support for said cutting tool, anair operated percussive motor connected to said support to impartmovement thereto for operating the cutting tool, said motor having anexhaust passageway positioned to discharge a stream of compressed airthrough said grooves and over the cutting surface of the tool to removeparticles tending to adhere to the tool.

EDWARD W. STEVENS.

